Anti-disturbance switch



March 5, 1968 J. L. BAKER ET AL ANTI-DISTURBANCE SWITCH 2 Sheets-Sheet 1 Filed May 19, 1958 INVENTORS JAMES L. BAKER a LAURENCE M ANDREWS March 5, 1968 J. BAKER ET AL 3,372,253

ANTI-DISTURBANCE SWITCH Filed May 19, 1958 2 Sheets-$heet 2 INVENTORS JAMES L. BAKER 8 LAURENCE M. ANDRE W8 BY if 41% United States Patent 3,372,253 Patented Mar. 5, 1968 3,372,253 ANTI-DISTURBANCE SWITCH James L. Baker, Bethesda, and Laurence M. Andrews, Silver Spring, Md., assignors, by mesne assignments, to the United States of America as represented by the Secretary of the Army Filed May 19, 1958, Ser. No. 736,409 2 Claims. (Cl. 20ll61.45)

The invention described herein may be manufactured and used by or for the Government for governmental purposes without the payment to us of any royalty thereon.

This invention relates to an improved anti-disturbance switch mechanism which is capable of closing a circuit and effecting detonation of an explosive if the switch is slightly vibrated, subjected to small forces acting in any direction, or tipped in any plane.

An important requirement of an anti-disturbance switch is that it be responsive to forces of disturbance acting in any direction. If the switch has this feature then only one switch need be used to make the device sensitive to disturbance forces acting in any direction. Another important requirement is that the switch be able to be attached to any object in any position. This requirement is particularly important when the switch must be attached to objects such as bombs or missiles where the switch may ultimately rest in any position after the bomb or missile impacts with the target. If the switch is to be used in booby-trap devices, it is essential that the switch have all the features referred to above, and have the additional features of being easily concealable and attachable to the object which is to be booby-trapped.

It is also desirable that the switch be sensitive to magnetic fields which may be used in attempts to disarm the explosive device in which the switch is incorporated.

As in many military devices, it is of further importance that the switch operate when subjected to adverse weather conditions such as extreme cold or heat.

Conventional anti-disturbance switches have not been able to satisfactorily provide all the features referred to above in one switch. The anti-disturbance switch of this invention, however, has all these features and utilizes the sensitivity to movement which a hard spherical body has when it rests upon hard smooth surfaces. The switch initiated detonation by closing an electrical circuit when the spherical body or hard surfaces experience movement caused by small disturbance forces acting in any direction. The anti-disturbance switch of this invention is designed to be open regardless of the initial position in which the switch is placed.

It is an object of this invention therefore, to provide an improved anti-disturbance switch which will initiate detonation of an explosive device in which the switch is incorporated if the device is disturbed.

It is another object of this invention to provide an antidisturbance switch which will be open while the switch is in any position when at rest and yet close in response to disturbance forces acting in any direction.

Another object is to provide a switch, which in addition to the above, will also be caused to close upon the application of magnetic fields.

A further object of this invention is to provide a compact switch having the above features which will operate satisfactorily at either high or low temperatures.

The specific nature of the invention, as well as other objects, uses, and advantages thereof, will clearly appear from the following description and from the accompanying drawing, in which:

FIGURE 1 is a side view of the switch in accordance with this invention.

FIGURE 2 is a plan view of the switch shown in FIG- URE 1.

FIGURE 3 is a partially exploded side view of the switch.

FIGURE 4 is a sectional plan view of the switch taken through lines 44 of FIGURE 1.

FIGURE 5 is a sectional side view taken through lines 5-5 of FIGURE 2.

FIGURE 6 is a perspective view of the switch with one of the covers removed, showing the position of the sphere when the switch is at rest in a tilted or tipped position.

FIGURE 7 is an end view of FIGURE 2 with a portion of the shell removed.

FIGURE 8 is a side elevation of the switch showing schematically the electrical circuit connecting the switch, detonator and battery.

In the drawing, a switch 10 has a hollow metallic cylindrical shell 11 with a series of inwardly projecting convex Wall segments 12. Convex wall segments 12 form between them and shell 11 a series of cavities 13 into which metal sphere 14 can rest. Disks 17 and 18 form upper and lower covers for the open ends of hollow shell 11 and are composed of any suitable electrical insulating material such as Bakelite, nylon or any epoxy resin. Disks 17 and 18 are substantially frusto-conical in shape as shown in FIGURE 5, and have inwardly tapering surfaces 19 and 20 which are preferably inclined at approximately 20 degrees with respect to the larger diameter ends of disks 17, 18.

Imbedded in the insulation of disks 17 and 18 are spur metal gears 25 and 26, having a series of equi-spaced teeth 27 and 28 extending outwardly from hubs 29 and 30, respectively. Teeth 27, 28, are ground flush with the tapered surfaces 19, 20 so as to be planar with these surfaces and provide a series of electrical conducting surfaces for the disks 17, 18. The outer extremities of teeth 27, 28 extend adjacent and opposite the convex wall segments 12 and are connected together at their innermost ends by hubs 29, 30. The ends of hubs 29 and 30 nearest the center of shell 11 form the frustums 29a, 30a for the tapered disks 17, 18 (FIGURE 5).

Hub ends 29a, 30a contact the ends of cylindrical hollow metal separator 23. Hubs 29 and 30 and cylindrical separator 23 have coaxial bores 17a, 18a, and 23a, respectively, into which metal bolt 40 can be inserted to align and connect the gears 25, 26 and separator 23. Gears 25, 26 are positioned centrally of disks 17, 18 and align disks 17, 18 in directions parallel to the longitudinal axis of shell 11. The head of bolt 40 contacts the outer recessed end 32 of hub 30 and is held by nut 41 which contacts outer recessed end 31 of hub 29.

Gear teeth 27, 28 extend outward from hubs 29 and 30, the outermost extremities of the gear teeth-26, 27 extend adjacent the innermost portions of the convex wall segments 12 and are insulated from the wall segments 12 and the shell 11 by the insulating material of disks 17, 18.

Affixed to the wall of shell 11 by soldering, for example, is electrical lead 43 which is connected to battery 44 (FIGURE 8) and to detonator 45. Lead 47 has one end soldered or otherwise fixed to the end of bolt 40 and to the detonator 45. The ends of leads 43 and 47 are electricaly connected to the detonator 45. Switch 48 is interposed in the circuit and can be opened or closed by moving one end in the direction of the arrows. Detonator 45 can be placed inside the main explosive charge of a mine, bomb or booby-trap (not shown).

It can be seen from the drawing that the improved switch of this invention is designed so that regardless of the position which the switch finally rests in, the

sphere 14 will come to rest in a cavity 13 where it will not complete the circuit of switch 10. If the switch is placed horizontally for example as shown in FIGURES l and 5, the combined effect of the tapered disks 17, 18, and the convex wall portions 12 will cause the sphere 14 to finally roll into a cavity 13. Or, should the switch 10 be placed or finally come to rest in the positions shown in FIGURES 6 or 7, the combined effect of the tapered disks 17, 18, and the convex wall segments 12 will again cause the sphere 14 to come to rest in one of the cavities 13. When the sphere 14 is in a cavity 13, it will not complete the contact between the teeth 27, 28 and the convex wall segments 12 so that the switch will be open. Any subsequent disturbance of the switch 10 will cause the sphere 14 to roll out of the cavity 13. When the sphere 14 rolls out of the cavity 13 over the extremity of one of the teeth of gears and 26 (as shown by the dotted lines in FIGURE 4), contact between a tooth and the innermost position of the wall segment 12 will be obtained so as to momentarily close the switch 10. It is evident from the drawing that it will require only small disturbance forces, regardless of their direction, to cause the sphere 14 to roll out of the cavity 13 and close the switch 10.

When it is desired to arm the switch 10', switch 48 is pressed downwards by manual pressure or by some member connected to a timing device (not shown). It is of course necessary that the switch 10 be at rest before the switch 48 is closed. Any subsequent movement of the switch 10 will cause the sphere 14 to roll and momentarily close the series circuit whereby battery 44 will activate detonator 45 causing detonation of the main charge of the booby-trap or bomb.

By making the sphere 14 of magnetic material, attempts to disarm the booby-trap or bomb by the use of magnetic forces will also cause the sphere 14 to roll out of the cavity 13 and momentarily close the switch .10.

In order to increase the shelf life of switch 10', the shell 11, gears 25, 26, separator 23 and sphere 14, should be made of brass or steel and coated with gold or any 1other appropriate noncorrosive and slow-oxidizing meta As will be apparent to those skilled in the art, the switch 10 can be made as sensitive as desired by increasing or decreasing the number of gear teeth 28, 29 and corresponding convex wall segments 12. If the number of gear teeth 28, 29 and wall segments 12 are reduced, then the sphere 14 will have to travel a greater distance over the disks 17 or 18 in order to make contact between a tooth and a corresponding wall segment 12. Also, the sensitivity of the switch can be increased by decreasing the angle of the tapered disks 17 or 18.

It will be apparent that the embodiments shown are only exemplary and that various modifications can be made in construction and arrangement within the scope of the invention as defined in the appended claims.

We claim as our invention:

1. An anti-disturbance switch comprising: a hollow metallic cylindrical shell having a series of equi-spaced,

inwardly projecting convex wall segments spaced around the shell circumference, said convex segments and said shell forming a series of cavities between successive convex wall segments, upper and lower tapered disks providing closures for the ends of said shell, said disks composed of an insulating material with surfaces tapering towards the shell center, a spur gear in said disk with tooth surfaces ground planar with the tapered surfaces of said disks, the outermost extremity of each tooth extending adjacent and opposite the innermost surface of a corresponding wall segment, said gear and shell acting as electrical conductors separated by the insulation of said disks, a metallic sphere in said shell, the tapered disks and convex wall segments causing said sphere to rest in a cavity when the switch is at rest, the diameter of said sphere being small enough so that the sphere makes no electrical contact between said convex wall segments and the teeth of said gear, said sphere being large enough so that when the sphere moves out of said cavity in response to disturbance of the switch it contacts the innermost surfaces of said convex wall segments and the outermost extremities of the gear teeth thus closing the circuit between the shell and gear.

2. An anti-disturbance switch comprising: a hollow metallic cylindrical shell having a series of equi-spaced, inwardly projecting convex wall segments spaced around the shell circumference, said convex segments and said shell forming a series of cavities between successive convex wall segments, upper and lower tapered disks providing closures for the ends of said shell, said disks composed of an insulating material with surfaces tapering abruptly towards the shell center, a series of electrical conductors having surfaces planar with the tapered surfaces of said disks and extending radially from the center of said disks at equally spaced intervals, the outermost extremity of each conductor extending adjacent and opposite a corresponding wall segment, said conductors being insulated from said shell and wall segments by the insulation of said disks, a first electrical lead afiixed to said shell, a second lead electrically connected to all conductors,.a metallic sphere in said shell, the tapered disks and convex wall segments causing said sphere to rest in a cavity when the switch is at rest, the diameter of said sphere being small enough so that the sphere makes no electrical contact between said inwardly projecting convex wall segments and said conductors when it rests in said cavity, the sphere diameter being large enough so that when the sphere moves out of said cavity in response to disturbance of the switch it contacts the innermost surfaces of said convex wall segments and the outermost extremities of said conductors, thus closing the electrical circuit between the shell and the conductors.

No references cited.

BERNARD A. GILHEANY, Primary Examiner.

FRED M. STRADER, GEORGE HARRIS, Examiners.

R. A, KUYPERS, Assistant Examiner. 

1. AN ANTI-DISTURBANCE SWITCH COMPRISING: A HOLLOW METALLIC CYLINDRICAL SHELL HAVING A SERIES OF EQUI-SPACED, INWARDLY PROJECTING CONVEX WALL SEGMENTS SPACED AROUND THE SHELL CIRCUMFERENCE, SAID CONVEX SEGMENTS AND SAID SHELL FORMING A SERIES OF CAVITIES BETWEEN SUCCESSIVE CONVEX WALL SEGMENTS, UPPER AND LOWER TAPERED DISKS PROVIDING CLOSURES FOR THE END OF SAID SHELL, SAID DISKS COMPOSED OF AN INSULATING MATERIAL WITH SURFACES TAPERING TOWARDS THE SHELL CENTER, A SPUR GEAR IN SAID DISK WITH TOOTH SURFACES GROUND PLANAR WITH THE TAPERED SURFACES OF SAID DISKS, THE OUTERMOST EXTREMITY OF EACH TOOTH EXTENDING ADJACENT AND OPPOSITE THE INNERMOST SURFACE OF A CORRESPONDING WALL SEGMENT, SAID GEAR AND SHELL ACTING AS ELECTRICAL CONDUCTORS SEPARATED BY THE INSULATION OF SAID DISKS, A METALLIC SPHERE IN SAID SHELL, THE TAPERED DISKS AND CONVEX WALL SEGMENTS CAUSING SAID SPHERE TO REST IN A CAVITY WHEN THE SWITCH IS AT REST, THE DIAMETER OF SAID SPHERE BEING SMALL ENOUGH SO THAT THE SPHERE MAKES NO ELECTRICAL CONTACT BETWEEN SAID CONVEX WALL SEGMENTS AND THE TEETH OF SAID GEAR, SAID SPHERE 